<template>
  <div>
      <button @click="isShow = true">点我弹个窗</button>
      <teleport to='body'>
        <div v-if="isShow" class="mask">
            <div  class="dialog">
          <h3>我是一个弹窗</h3>
          <h4>一些内容</h4>
          <h4>一些内容</h4>
          <h4>一些内容</h4>
          <h4>一些内容</h4>
          <button @click="isShow = false">关闭弹窗</button>
      </div>
        </div>
      </teleport>
  </div>
</template>

<script>
import { ref } from 'vue'
export default {
  name:'Dialog',
  setup() {
      let isShow = ref(false)
      return {isShow}
  }
}
</script>

<style>
 .mask {
position: absolute;
top: 0;
left: 0;
right: 0;
bottom: 0;
background-color: rgba(0, 0, 0,0.5);
}
 .dialog {
     position: absolute;
     left: 50%;
     top: 50%;
     transform: translate(-50%,-50%);
     text-align: center;
     width: 300px;
     height: 300px;
     background-color: green;
 }
</style>